CVE-2025-24839: Mattermost Server

Medium severity, CVSS 4.3. EPSS: 0.2% chance of exploitation in the next 30 days.

Mattermost versions 10.5.x <= 10.5.1, 10.4.x <= 10.4.3, 9.11.x <= 9.11.9 fail to prevent Wrangler posts from triggering AI responses. This vulnerability allows users without access to the AI bot to activate it by attaching the activate_ai override property to a post via the Wrangler plugin, provided both the AI and Wrangler plugins are enabled.

Affected products

• Mattermost Mattermost Server: from 9.11.0, before 9.11.10 (fixed in 9.11.10); from 10.4.0, before 10.4.4 (fixed in 10.4.4); from 10.5.0, before 10.5.2 (fixed in 10.5.2)

Published 2025-04-16. Last modified 2026-06-17.